Gene variant reduces poor childhood lung function risk

Abstract

medwireNews: Children carrying a gene variant for a receptor involved in airway relaxation have a lower risk for poor lung function at 10 years of age than other children, regardless of gender and exposure to pets or tobacco smoke, say Norwegian researchers.

Tale Torjussen, from Oslo University Hospital, and colleagues studied 953 children from the prospective Environment and Childhood Asthma birth cohort study, in which tidal flow volume was measured at a mean of 2.7 days after birth and spirometry was performed at 10-year follow-up. In addition, the children were genotyped for four common single nucleotide polymorphisms (SNPs) in the ADRB2 gene: rs1042713, rs1042714, rs1800888 and rs1042711.

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The three most common haplotypes were CGGC, TACC, and TGCC, which, at a prevalence of 43.1%, 38.6%, and 16.9%, respectively, covered 98.6% of all haplotypes.

Among newborn babies, 16% had reduced lung function, while 5% of 10-year-olds had reduced lung function. Multiple testing did not reveal any associations between lung function at birth or at 10 years and individual SNPs or single haplotypes, the authors report in Acta Paediatrica.

However, children with the CGGC haplotype were significantly less likely than other children to have reduced lung function (forced expiratory volume at 1 second, predicted ≤5th percentile) at 10 years of age with an odds ratio of 0.45.

There were no associations between ADRB2 genotypes or haplotypes and changes in lung function measurements from birth to 10 years, persistently reduced lung function, or a shift from normal lung function at birth to reduced lung function at 10 years, or vice versa. Tobacco smoke exposure at 10 years and in utero, gender, and pet-keeping were also not significantly associated with ADRB2 haplotypes.

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The ADRB2 gene encodes the beta-2-adrenergic receptor, which is expressed in airway smooth muscle and induces bronchial relaxation, explain the authors. SNPs in the gene have repeatedly been shown to be associated with bronchodilation and asthma, but less is known about its role in lung function development.

"Our results may imply that ADRB2 genes contribute to lung function development in childhood, independently of gender and exposure to tobacco smoke and pets," Torjussen and colleagues conclude.